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  1. Article ; Online: Photosensitized isomerization of resveratrol: Evaluation of energy and electron transfer pathways.

    Neyra Recky, Jael R / Gaspar Tosato, Maira / Buglak, Andrey A / Dántola, M Laura / Lorente, Carolina

    Free radical biology & medicine

    2024  Volume 216, Page(s) 50–59

    Abstract: Resveratrol (3,5,4'-trihydroxystilbene, RSV) is a natural stilbene synthetized as trans-isomer in plants exposed to oxidative stress. In order to understand the mechanism involved during photosensitized degradation of trans-resveratrol, steady-state and ... ...

    Abstract Resveratrol (3,5,4'-trihydroxystilbene, RSV) is a natural stilbene synthetized as trans-isomer in plants exposed to oxidative stress. In order to understand the mechanism involved during photosensitized degradation of trans-resveratrol, steady-state and time-resolved experiments were performed and compared with quantum-chemical calculations using density functional theory (DFT). Pterin (Ptr), a well-known photosensitizer, under UV-A radiation induces the oxidation of several biomolecules mainly through electron-transfer mechanisms. On the one hand, it was observed that trans-RSV participates in an energy-transfer pathway with Ptr triplet excited state (
    MeSH term(s) Resveratrol ; Isomerism ; Electrons ; Antioxidants/chemistry ; Pterins/pharmacology
    Chemical Substances Resveratrol (Q369O8926L) ; Antioxidants ; Pterins
    Language English
    Publishing date 2024-01-23
    Publishing country United States
    Document type Journal Article
    ZDB-ID 807032-5
    ISSN 1873-4596 ; 0891-5849
    ISSN (online) 1873-4596
    ISSN 0891-5849
    DOI 10.1016/j.freeradbiomed.2024.01.038
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.A 2109: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
    ab Jg. 2022: Lesesaal (EG)

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  2. Article ; Online: Avoiding One-Electron Oxidation of Biomolecules by 3,4-Dihydroxy-L-Phenylalanine (DOPA)

    Neyra Recky, Jael R / Dántola, M Laura / Lorente, Carolina

    Photochemistry and photobiology

    2022  Volume 99, Issue 2, Page(s) 570–579

    Abstract: It has been proposed that 3,4-dihydroxy-L-phenylalanine (DOPA) has antioxidant properties, and thus, the objective of this work was to evaluate the effect of adding DOPA during the photosensitized oxidation of tyrosine (Tyr), tryptophan (Trp), histidine ( ...

    Abstract It has been proposed that 3,4-dihydroxy-L-phenylalanine (DOPA) has antioxidant properties, and thus, the objective of this work was to evaluate the effect of adding DOPA during the photosensitized oxidation of tyrosine (Tyr), tryptophan (Trp), histidine (His), 2'-deoxyguanosine 5'-monophosphate (dGMP) and 2'-deoxyadenosine 5'-monophosphate (dAMP). It was observed that, upon pterin-photosensitized degradation of a given biomolecule in acidic aqueous solutions, the rate of the biomolecule consumption decreases due to the presence of DOPA. Although DOPA deactivates the excited states of pterin (Ptr), biomolecules do as well, being the bimolecular quenching constants in the diffusional control limit, indicating that DOPA antioxidant mechanism is not a simple deactivation of Ptr excited states. Laser flash photolysis experiments provide evidence of the formation of DOPA radical (DOPA(-H)
    MeSH term(s) Antioxidants/metabolism ; Electrons ; Oxidation-Reduction ; Pterins ; Levodopa/metabolism ; Photolysis
    Chemical Substances Antioxidants ; Pterins ; Levodopa (46627O600J)
    Language English
    Publishing date 2022-10-25
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 123540-0
    ISSN 1751-1097 ; 0031-8655
    ISSN (online) 1751-1097
    ISSN 0031-8655
    DOI 10.1111/php.13718
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.B 1686: Show issues Location:
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  3. Article ; Online: Oxidation of tyrosine: Antioxidant mechanism of l-DOPA disclosed.

    Neyra Recky, Jael R / Serrano, Mariana P / Dántola, M Laura / Lorente, Carolina

    Free radical biology & medicine

    2021  Volume 165, Page(s) 360–367

    Abstract: Tyrosine is an amino acid related to crucial physiological events and its oxidation, that produce beneficial or detrimental effects on biological systems, has been extensively studied. Degradation of tyrosine often begins with the loss of an electron in ... ...

    Abstract Tyrosine is an amino acid related to crucial physiological events and its oxidation, that produce beneficial or detrimental effects on biological systems, has been extensively studied. Degradation of tyrosine often begins with the loss of an electron in an electron transfer reaction in the presence of a suitable electron acceptor. The reaction is facilitated by excited states of the acceptor in photosensitized processes. Several products of tyrosine oxidation have been described, the main ones being 3,4-dihydroxy-l-phenylalanine (commonly known as DOPA) and tyrosine dimers. Here, we report tyrosine recovery from tyrosyl radical, after one-electron oxidation, in the presence of DOPA. We propose that under high oxidative stress the oxidation of tyrosine may be controlled, in part, by one of its oxidation products. Also, we present strong evidence of antioxidant action of DOPA by preventing tyrosine dimerization, one of the most serious oxidative protein modifications, and the origin of structural modifications leading to the loss of protein functionality.
    MeSH term(s) Antioxidants ; Levodopa ; Oxidation-Reduction ; Proteins/metabolism ; Tyrosine/metabolism
    Chemical Substances Antioxidants ; Proteins ; Tyrosine (42HK56048U) ; Levodopa (46627O600J)
    Language English
    Publishing date 2021-01-29
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 807032-5
    ISSN 1873-4596 ; 0891-5849
    ISSN (online) 1873-4596
    ISSN 0891-5849
    DOI 10.1016/j.freeradbiomed.2021.01.037
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.A 2109: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
    ab Jg. 2022: Lesesaal (EG)

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  4. Article ; Online: Photosensitized Dimerization of Tyrosine: The Oxygen Paradox.

    Dántola, M Laura / Neyra Recky, Jael R / Lorente, Carolina / Thomas, Andrés H

    Photochemistry and photobiology

    2021  Volume 98, Issue 3, Page(s) 687–695

    Abstract: In electron-transfer initiated photosensitization processes, molecular oxygen ( ... ...

    Abstract In electron-transfer initiated photosensitization processes, molecular oxygen (O
    MeSH term(s) Dimerization ; Oxidation-Reduction ; Oxygen ; Pterins/chemistry ; Singlet Oxygen/chemistry ; Tyrosine/chemistry
    Chemical Substances Pterins ; Singlet Oxygen (17778-80-2) ; Tyrosine (42HK56048U) ; Oxygen (S88TT14065)
    Language English
    Publishing date 2021-11-17
    Publishing country United States
    Document type Journal Article ; Review ; Research Support, Non-U.S. Gov't
    ZDB-ID 123540-0
    ISSN 1751-1097 ; 0031-8655
    ISSN (online) 1751-1097
    ISSN 0031-8655
    DOI 10.1111/php.13557
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.B 1686: Show issues Location:
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  5. Article ; Online: Pterin-photosensitization of thymine under anaerobic conditions in the presence of guanine.

    Estébanez, Sandra / Rivera, Ana M / Neyra Recky, Jael R / Thomas, Andrés H / Lhiaubet-Vallet, Virginie / Lorente, Carolina

    Free radical biology & medicine

    2021  Volume 174, Page(s) 321–328

    Abstract: Pterin (Ptr) is a model photosensitizer that acts mainly through type I mechanism and is able to photoinduce the one-electron oxidation of purine and pyrimidine nucleobases. However, under anaerobic conditions Ptr reacts with thymine (T) to form ... ...

    Abstract Pterin (Ptr) is a model photosensitizer that acts mainly through type I mechanism and is able to photoinduce the one-electron oxidation of purine and pyrimidine nucleobases. However, under anaerobic conditions Ptr reacts with thymine (T) to form photoadducts (Ptr-T) but does not lead to the photodegradation of guanine (G), which is the nucleobase with the lowest ionization potential. Accordingly, G is thermodynamically able to reduce the radicals of the other nucleobases and has been described in this sense as the "hole sink" of the DNA double helix. Here we analyze by steady-state and time-resolved studies the effect of G in the anaerobic photosensitization of T by Ptr, using nucleotides and oligonucleotides of different sequences. We demonstrated that G is able to reduce T radicals but does not prevent the formation of Ptr-T adducts. Our results suggest that after the encounter between the excited Ptr and T, and completion of the electron transfer step, part of the radicals escape from the solvent cage, to further react with other species. However, a proportion of radicals do not escape and evolve to photoadducts before separation. We provide new evidence that contributes to understand the photosensitizing properties of Ptr in the absence of O
    MeSH term(s) Anaerobiosis ; Guanine ; Oxidation-Reduction ; Pterins ; Thymine
    Chemical Substances Pterins ; Guanine (5Z93L87A1R) ; Thymine (QR26YLT7LT)
    Language English
    Publishing date 2021-07-30
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 807032-5
    ISSN 1873-4596 ; 0891-5849
    ISSN (online) 1873-4596
    ISSN 0891-5849
    DOI 10.1016/j.freeradbiomed.2021.07.032
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.A 2109: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
    ab Jg. 2022: Lesesaal (EG)

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  6. Article ; Online: Evidence of the effectiveness of Resveratrol in the prevention of guanine one-electron oxidation: possible benefits in cancer prevention.

    Neyra Recky, Jael R / Gaspar Tosato, Maira / Serrano, Mariana P / Thomas, Andrés H / Dántola, M Laura / Lorente, Carolina

    Physical chemistry chemical physics : PCCP

    2019  Volume 21, Issue 29, Page(s) 16190–16197

    Abstract: Over the past few years, the interest in Resveratrol (3,4',5,-trihydroxystilbene, RSV) has increased due to the evidence found of its antioxidant action that protects biomolecules and cells from oxidative damage. The interest has been further exacerbated ...

    Abstract Over the past few years, the interest in Resveratrol (3,4',5,-trihydroxystilbene, RSV) has increased due to the evidence found of its antioxidant action that protects biomolecules and cells from oxidative damage. The interest has been further exacerbated by the natural presence of RSV in some fruits and derivatives, especially in red wine. In this paper we present evidence of RSV capacity in protecting a deoxynucleotide, an essential constituent of DNA, from one-electron oxidation. This article evaluates the mechanism responsible for the antioxidant action of RSV, after one-electron oxidation of 2'-deoxyguanosine 5'-monophosphate (dGMP), by kinetic analysis during steady-state irradiation and laser flash photolysis experiments. Results showed that RSV protects dGMP by recovering the nucleotide from its radical, which is formed after the reaction of dGMP with the triplet excited state of the photosensitizer. In the absence of RSV, dGMP is irremediably oxidized, and if the damage occurs in dGMP located in DNA molecules, the consequences can be as serious as mutations and subsequent carcinogenic lesions.
    MeSH term(s) Antioxidants/chemistry ; Antioxidants/pharmacology ; Electrons ; Guanine/chemistry ; Neoplasms/prevention & control ; Oxidation-Reduction/drug effects ; Resveratrol/chemistry ; Resveratrol/pharmacology
    Chemical Substances Antioxidants ; Guanine (5Z93L87A1R) ; Resveratrol (Q369O8926L)
    Language English
    Publishing date 2019-07-10
    Publishing country England
    Document type Journal Article
    ZDB-ID 1476244-4
    ISSN 1463-9084 ; 1463-9076
    ISSN (online) 1463-9084
    ISSN 1463-9076
    DOI 10.1039/c9cp03027a
    Database MEDical Literature Analysis and Retrieval System OnLINE

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